1. Field of the Invention
The present invention relates to a cylinder lock having a flat slide plate with at least one hole for receiving pin tumblers and at least one indent for receiving side bar pins.
2. Description of the Related Art
The idea of designing a cylinder lock with pin tumblers, driver tumblers having a constant pressure from a spring, and using a key to make the pin tumblers align with the surface of a plug in order to free it and let it rotate have been known since they were discovered by Linius Yale late in the last century.
In fact, a very similar system was used in the old Egyptian culture which included wood pins, drivers, and a key. Of course, that ancient lock was considerably larger than that designed by Mr. Yale.
Following the above-noted early developments, a German company known as DOM created a new cylinder in which, instead of having the key bitings on the upper part, they were put into its flat surface.
Since that time, a great deal of effort has been devoted to developing a system to open the Yale-type cylinder like pinning, vibration, and the like. Because of such problems, lock manufacturers have developed special systems in order to make opening the cylinder more difficult. For example, Medeco considerably improved the security of his cylinder by means of making the pins turn in order to allow a side-bar to reach the opening position. Schlague developed a "finger pins" cylinder. Even further, Valerio Poli, the father of the inventor of the subject invention, in late 1965 developed a cylinder in which four pin tumblers faced another four pin tumblers and received a U.S. Patent therefor. Thus, various top security cylinders have been developed over the past several years.